1. Field of the Invention
The present invention relates to an apparatus for controlling a motor, and more particularly, to a motor control apparatus for stably controlling a motor without adding a separate hardware when operating the motor at a high speed, and a method of the same.
2. Background of the Invention
Motors provided in a compressor typically do not include a sensor due to the difficulty of its installation. Accordingly, a control apparatus for driving the motor drives the motor using a sensorless algorithm. The sensorless algorithm calculates the position of a rotor to allow the user to drive the motor at his or her desired speed. A motor control apparatus according to the related art may be operated up to a predetermined machine speed, for example, 120 Hz (hereinafter, normal operation), using this sensorless algorithm, but high-speed operation, for example, 150 Hz, is required to enhance the performance of a compressor.
In order to operate a motor at a high speed, the stability of control should be secured and load responsiveness should be enhanced (hereinafter, control resolution). If the speed of a motor is increased, then there is a problem that the sampling period is shortened, and the sampling number of a current applied to the motor is reduced from 21 to 17 when increasing the speed with a control algorithm driven during normal operation and thus the control resolution should be increased.
In a motor control apparatus according to the related art, carrier frequency is increased to improve control resolution. However, the method of increasing carrier frequency increases control resolution, but has a problem of increasing the number of switching, thereby causing switching loss.